Method of forming a tubular member

ABSTRACT

A method for roll-forming a tubular member is provided. The method includes providing a roll-forming machine having a pair of rollers and a forming roller adjacent the pair of rollers. Further, cutting a strip of sheet metal to form a segment having free leading and trailing ends extending between a predetermined length; feeding the segment between the pair rollers; calculating the thickness of the segment via feedback from the pair of rollers; automatically adjusting the position of the forming roller in response to the determined thickness of the segment; advancing the segment between the pair of rollers and against the forming roller to form an annulus; and forming a weld joint between the free ends.

CROSS REFERENCE TO RELATED APPLICATION

This continuation application claims priority to U.S. Utilityapplication Ser. No. 13/176835, filed Jul. 6, 2011, and is incorporatedherein by reference.

BACKGROUND OF THE INVENTION

1. Technical Field

This invention relates generally to methods of forming tubular members,and more particularly to methods of rolling and welding tubular members,

2. Related Art

It is well known to form metal tubular members from flat sheet materialby rolling a fixed length of the sheet material into a tubular form andthen welding abutting ends of the rolled sheet to one another to formeda length-wise extending welded seam. However, in forming rolled tubularmembers, challenges remain in being able to form the tubular memberhaving tightly controlled inner or outer diameter tolerances. Further,challenges remain in being able to form the tubular member having apurely cylindrical shape. Typically, a flat surface is formedimmediately adjacent the welded seam, resulting from a small segment ofthe flat sheet material not being curled. Further yet, challenges remainin forming tightly controlled diameter tolerances due to inherentvariation in the actual sheet material thickness due to thicknesstolerances of the sheet material. Accordingly, the inner and/or outerdiameter of formed with one sheet material thickness is generallydifferent from the inner and/or outer diameter of another sheet materialthickness. When these tolerances are critical to the performance of thetubular member and components associate therewith, the useful life ofthe tubular member and/or components can be reduced.

A method of forming a tubular member from a generally flat piece ofmetal sheet material in accordance with invention overcomes thechallenges discussed above, as well as others, which will be readilyapparent to those possessing ordinary skill in the art of formingtubular members from metal sheet material.

SUMMARY OF THE INVENTION

In accordance with one aspect of the invention, a method forroll-forming tubular member is provided, The method includes providing aroll-forming machine having a pair of rollers and a forming rolleradjacent the pair of rollers. Further, cutting a strip of sheet metal toform a segment having free leading and trailing ends extending between apredetermined length; feeding the segment between the pair rollers;calculating the thickness of the segment via feedback from the pair ofrollers; automatically adjusting the position of the forming roller inresponse to the determined thickness of the segment; advancing thesegment between the pair of rollers and against the forming roller toform an annulus; and forming a weld joint between the free ends.

In accordance with another aspect of the invention, the method furtherincludes blanking the sheet metal and forming the leading end of thesegment having a predetermined radius of curvature corresponding to theradius of curvature of the annulus.

In accordance with another aspect of the invention, the method furtherincludes moving the forming roller to compensate for the thickness ofthe segment to provide the annulus with at least one of a predeterminedinner diameter and/or outer diameter.

In accordance with another aspect of the invention, a further method forroll-forming a tubular member is provided. The method includes providinga roll-forming machine having a pair of rollers and a forming rolleradjacent the pair of rollers, Further, cutting a strip of sheet metal toform a segment having free leading and trailing ends extending between apredetermined length, wherein the cutting is performed by blanking thesheet metal and forming the leading end of the segment having apredetermined radius of curvature. Then, feeding and advancing thesegment between the pair of rollers and against the forming roller toform an annulus and forming a weld joint between the free ends.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects, features and advantages of the presentinvention will become more readily appreciated when considered inconnection with the following detailed description of presentlypreferred embodiments and best mode, appended claims and accompanyingdrawings, in which:

FIG. 1 is a perspective view of a tubular member constructed inaccordance with one aspect of the invention;

FIG. 2 is a cross-sectional view of the tubular member of FIG. 1;

FIG. 3 is a schematic side view of a segment of sheet metal being cut tolength;

FIG. 4 is a schematic front view of a rolling apparatus constructed inaccordance with one aspect of the invention

FIG. 4a is an enlarged fragmentary schematic view of a portion of FIG. 4where the strip passes between the rollers; and

FIG. 5 is a process flow chart of a process for forming a tubular memberin accordance with one aspect of the invention.

DETAILED DESCRIPTION OF PRESENTLY PREFERRED EMBODIMENTS

Referring in more detail to the drawings, FIG. 1 illustrates a tubularmember 10, represented as an automatic transmission clutch apply ring,by way of example and without limitation, constructed in accordance withone presently preferred embodiment of the invention. The tubular member,referred to hereafter simply as annulus or ring 10, is constructed fromsheet metal strip material 12, such as from steel, which is commonlysupplied in coiled form. The steps used to form the ring 10 illustratedin FIGS. 1 and 2, by way of example, are shown in a process flow chartof FIG. 5, which include the following steps: cutting metal sheetmaterial 12 to a predetermined width to form an elongate strip of thematerial and optionally the sheet material 100, and then, if coiled,uncoiling the cut strip material 12 and straightening the strip material200. Further, the straightened strip material 12 is processed in acutting operation 300 to form segments 14 having a predetermined length(l) sufficient to form the ring diameter desired. Then, the cut segments14 are formed in a rolling operation 400 by a servo-controlledroll-forming machine 16 (FIG. 4) that produces the annular shape of thering 10. Further, the ring 10 is pushed, such as via a hydrauliccylinder, for example, from the roll forming machine 16 to a weldingstation 500. Then, the ring 10 is clamped in the welding station 600whereupon opposite ends 18, 20 of the ring 10 are welded to one anotherin a welding operation 700, such as via a laser welding operation, byway of example and without limitation. Then, the weld joint is checkusing feedback from a weld monitoring system 750 to verify that the weldjoint meets specification. if the weld joint is flawed, the ring 10 isthen sent to scrap 775. However, if the weld joint meets specification,then the ring 10 is ejected from the welding station, such as via ahydraulic cylinder, for example, and transferred to a sizing and flangespin-forming machine 800. Further operations can then optionally beperformed, depending on the intended application of the ring 10, such asshown in steps 800-1400, For example, the ring 10 can be ejected fromthe welding station and transferred to a sizing and flange spin-formingmachine 800, such as via a hydraulic cylinder, for example. Then, asizing process 900 can be performed on the ring 10 to bring the ring tothe precise size desired, such as via a hydraulic expanding mandrel.Further, the ring 10 can be further processed via a spin-forming process1000 to form a flange or flanges on outer edges of the ring 10, such asvia a servo-controlled spin device, for example. Then, the ring 10 canbe transferred to a piercing process 1100 and then notches and/oropenings can be formed in a wall of the ring 10, as desired. Theprocessed ring 10 is then inspected via a suitable ring gauge 1150,whereupon the ring 10 is sent to scrap 1175 if failing inspection, orsent to finished product if passing inspection. Optionally, the ring 10can be further processed in a plating operation, if desired for theintended application.

The roll-forming machine 16 has a pair of rollers 22,24 and a formingroller 26 adjacent the pair of rollers 22, 24 as illustrated in FIGS. 4and 4 a. In addition, the roll-forming machine 16 has a plurality ofrollers 27 separate from the pair of rollers 22, 24 and forming roller26. The pair of rollers are provided as a feed roller 22 and a pinchroller 24. The feed roller 22 is driven about a fixed axle 28, while thepinch roller 24 rotates about an axle 30 in response to engagement withthe advancing strip material 12. The axle 30 supporting the pinch roller24 is movable toward and away from the feed roller axle 28. In theroll-forming process 400, with the segment 14 of strip material 12advanced to or slightly beyond a tangent point 32 on the feed roller 22,the pinch roller 24 is moved toward the feed roller 22 into abutmentwith the strip material 12 to a predetermined pressure. The pressure isdetermined via an electronic feedback loop, wherein the pressure and thedistance of movement of the pinch roller 24 are used to automaticallycalculate the thickness (t) of the segment 14. Then, prior to formingthe ring 10, the forming roller 26 and the plurality of rollers 27 areautomatically moved along radially extending slots to a calculatedradial position in response the calculated thickness (t) that results informing the ring with a precise diameter (2>R) desired. As such, anyvariability of the ring diameter that would otherwise result fromthickness tolerances of the strip material are automatically accountedand adjusted for. The segment 14 is then advanced to abut a tangentpoint 33 on the forming roller 26 and into abutment with the pluralityof rollers 27 to form the ring having a predetermined radius ofcurvature (R), whereupon the ends 18, 20 are welded in the weldingprocess 700, whereupon further processing, e.g., spin forming, sizing,piercing, machining, and plating, for example, are then performed.

As shown in FIG. 3, to facilitate forming the ring 10 having a purelycylindrical wall, without any flat sections, the cutting operation formsa radiused end portion 34 of the segments 14 with a predetermined radiusof curvature (r) via a cutting blade 36. The radiused end portion 34extends from the free end 18 over a distance (d) equal to or slightlygreater than a distance (D) between the tangent points 32, 33 of thefeed roller 22 and forming roller 26 (FIGS. 4 and 4A). The predeterminedradius of curvature (r) is provided having the same or substantially thesame radius of curvature (R) as the annulus 10. As such, the end portion34, which would tend to remain flat or substantially flat if notpre-curled upon forming the ring 10, takes on a continuously curvedradius of curvature r along with the remain portion of the segment 14,thereby providing the ring 10 with a continuous radius of curvature Rabout its entire circumference.

The cutting blade 36 used in the blanking process has a leading cuttingedge 38 and a trailing cutting edge 40, with a radiused surface 42extending therebetween, The radiused surface 42 has a radius r′, whichcorresponds to (r+t), to produce the radiused end portion 34. Tofacilitate forming the radiused end portion 34, a mandrel 44 with anouter cylindrical surface 46 with a radius r″, being equal to orsubstantially equal to r, is used in combination with the cutting blade36. The mandrel 44 underlies the end portion 34 of the segment 14 duringblanking, such that as the cutting blade 36 blanks the strip material12, the strip material 12 bends around the outer surface 46 of themandrel 44,

Upon blanking the segment 14, the segment 14 is further processed asdiscussed above and as shown in the process flow chart of FIG. 5.

Many modifications and variations of the present invention are possiblein light of the above teachings. It is, therefore, to be understood thatthe invention may be practiced otherwise than as specifically described,and that the scope of the invention is defined by any ultimately allowedclaims,

What is claimed is:
 1. A method for roll-forming a tubular member,comprising: providing a roll-forming machine having a pair of rollersincluding a feed roller driven on a fixed feed roller axle and a pinchroller supported on an axle that is moveable toward and away from thefeed roller axle, and a forming roller adjacent the pair of rollers;cutting a strip of sheet metal to form a segment having free leading andtrailing ends extending between a predetermined length; feeding thesegment between the pair of rollers; moving the pinch roller over ameasured distance into abutment with the segment to a predeterminedpressure and calculating the thickness of the segment via thepredetermined pressure and the measured distance of the pinch-roller;automatically adjusting the position of the forming roller in responseto the thickness of the segment calculated via the measured distance andpressure feedback from the pinch roller; advancing the segment betweenthe pair of rollers and against the forming roller to form an annulus;and forming a weld joint between the free ends.
 2. The method of claim 1further including performing the cutting by blanking the sheet metalwith a cutting blade and forming the leading end of the segment having apredetermined radius of curvature with the cutting blade having aleading cutting edge and a trailing edge, the cutting blade having aradiused surface extending between the leading cutting edge and thetrailing edge, wherein the radiused surface of the cutting blade formsthe predetermined radius of curvature.
 3. The method of claim 2 furtherincluding forming the predetermined radius of curvature havingsubstantially the same radius of curvature as the annulus. 4, The methodof claim 2 further including forming the predetermined radius extendingover a distance substantially equal to the distance between tangentpoints of the pair of rollers and forming roller against which thesegment abuts.
 5. The method of claim 1 further including automaticallymoving the forming roller to compensate for the thickness of the segmentto provide the annulus with a predetermined inner diameter via theposition of the forming roller.
 6. The method of claim 1 furtherincluding automatically moving the forming roller to compensate for thethickness of the segment to provide the annulus with a predeterminedouter diameter via the position of the forming roller.
 7. The method ofclaim 1 further including providing the roll-forming machine having aplurality of rollers separate from the pair of rollers and the formingroller.
 8. The method of claim 7 further including automaticallyadjusting the position of the plurality of rollers in response to thedetermined thickness of the segment.
 9. The method of claim 1 furtherincluding expanding the annulus in a sizing process.
 10. The method ofclaim 9 further including spin forming an annular flange on said cumulussimultaneously with the sizing process.
 11. The method of claim 10further including forming at least one notch in the cumulus.
 12. Themethod of claim 10 further including forming at least one opening in theannulus.